The following background information may present examples of specific aspects of the prior art (e.g., without limitation, approaches, facts, or common wisdom) that, while expected to be helpful to further educate the reader as to additional aspects of the prior art, is not to be construed as limiting the present invention, or any embodiments thereof, to anything stated or implied therein or inferred thereupon.
Continuously Variable Transmissions (CVTs) are mechanical transmission systems that may be used to continuously and steplessly vary the velocity and torque ratio between an input and an output shaft. Toroidal traction CVTs generally have symmetrical specially shaped input and output discs or wheels with a variator wheel between the output discs or wheels to vary the ratio between the input and output discs or wheels. Traction Toroidal Transmissions transmit power between the wheels by shearing action of traction fluid trapped between the wheels without actual physical contact. The velocity and torque ratio of a typical toroidal traction CVT generally directly related to the angle of the variator wheel.
Toroidal traction CVTs typically come in two topologies: half toroidal and full toroidal. In half toroidal topologies, the variator wheel pivots off-center of the toroidal cavity; the pivot is not in the center of the circle formed between the input and output wheels which is a hollow circular cross section of the toroidal cavity. In full toroidal topologies, the variator wheel pivots in the exact center of the circle formed between the input and output wheels which is a hollow circular cross section of the toroidal cavity.
The following is an example of a specific aspect in the prior art that, while expected to be helpful to further educate the reader as to additional aspects of the prior art, is not to be construed as limiting the present invention, or any embodiments thereof, to anything stated or implied therein or inferred thereupon. By way of educational background, another aspect of the prior art generally useful to be aware of is that conventional toroidal traction CVTs typically use symmetrical input and output discs or wheels. These CVTs typically have a velocity and torque ratio range of about 2:1 to 2.65:1 (or vice versa). Wider ratio ranges are typically achieved by connecting multiple stages of CVTs together or/and adding supplementary gear arrangement at the output shaft such as suitable epicyclical gear trains.
In view of the foregoing, it is clear that these traditional techniques are not perfect and leave room for more optimal approaches.
Unless otherwise indicated illustrations in the figures are not necessarily drawn to scale.